October 13, 2010

Genetic Tests No Better At Predicting Disease Than Family History

Medical experts are now telling consumers to be cautious about genetic tests that claim to predict various diseases.

Researchers in Australia said risk factors like smoking, lack of exercise, age, hypertension and family history were more reliable predictors than genetic tests.

"Studies done for diabetes, heart disease and common cancers have identified a large number of genes associated with increased risk of developing (these diseases)," lead author Wayne Hall, a professor at the University of Queensland Center for Clinical Research, told Reuters.

"But the liability and increased risk of any one of these genes is often trivially small ... it's not information you can act on," he added.

There have been long-term studies tracking large numbers of people over time to see if those with certain gene mutations can later develop associated diseases. However, Hall said that genetic information was not better at predicting disease.

"In general, adding the genetic information doesn't improve on the ability to predict over and above what you know about existing risk factors," he told Reuters.

"So knowing that you smoke, blood pressure, your gender, family history and age; they are still good predictors of disease risk and genetic information usually doesn't do as well as those fairly crude predictors of disease risk."

The research, which was published in PLoS Medicine, comes as consumers are overwhelmed with more genetic testing being offered that claim to predict many different types of diseases.

"I wouldn't purchase any of these tests myself. They have very limited use and if I have reason to suspect I have some gene that is strongly predictive of disease risk, I will go through a proper genetic testing curriculum because there is very little value in these genome-wide scans that are being marketed," Hall said.